Technique for migrating a snapshot storage service during a planned failover event

Abstract

A service migration technique moves (migrates) a snapshot storage service of an archival storage system from a primary site to a secondary site in accordance with a planned failover event. The snapshot storage service is configured to provide storage and retrieval of large amounts of snapshots (e.g., recovery points) of application workloads stored as objects on one or more buckets of an object store. As part of finalization of the recovery points (RPs) at the primary site, the snapshot storage service stores snapshot data and metadata of the RPs (e.g., as service state) in the object store. The snapshot storage service may then be migrated to the secondary site, wherein migration involves terminating the service at the primary site and instantiating the service at the secondary site. The instantiated storage service instance may then rebuild its service state from the object store, and resume storage and retrieval operations directed to RPs serviced by the instance.

What is claimed is: 
     
         1 . A method comprising:
 receiving one or more replicated snapshots at an instance of a snapshot storage service for storage and retrieval of snapshots, the snapshot storage service instance executing on a computing node proximate a primary site, the snapshots replicated in accordance with snapshot replication transfers of a replication transaction from a client;   marking the snapshot storage service instance to reject generation of new snapshots;   finalizing the snapshots by completing index data structures configured to identify locations of the snapshots on an object store, wherein finalizing includes storing snapshot data and metadata as a service state of the snapshots committed to the object store;   terminating the snapshot storage service instance proximate the primary site;   instantiating another instance of the snapshot storage service at a secondary site; and   rebuilding the service state of the another snapshot storage service instance from the object store and resume storage and retrieval operations of the snapshots serviced by the another snapshot storage instance.   
     
     
         2 . The method of  claim 1  further comprising, in response to marking the snapshot storage service instance, waiting for inflight snapshot replication transfers to complete and finalize. 
     
     
         3 . The method of  claim 1  further comprising, in response to marking the snapshot storage service instance, aborting inflight snapshot replication transfers after elapse of a configurable period of time. 
     
     
         4 . The method of  claim 3  wherein the configurable period of time approximates a recovery point objective. 
     
     
         5 . The method of  claim 1  wherein marking of the snapshot storage service instance comprises asserting a flag that indicates to the snapshot storage service instance to notify the client to cease generation of new snapshots. 
     
     
         6 . The method of  claim 5  further comprising de-asserting the flag to notify the client to resume replication of the snapshots to the another snapshot storage service instance at the secondary site. 
     
     
         7 . The method of  claim 5  further comprising de-asserting the flag to notify the client to initiate further snapshot replication transactions to the another snapshot storage service instance at the secondary site. 
     
     
         8 . The method of  claim 1  further comprising determining committed snapshots during the rebuild of the another snapshot storage service. 
     
     
         9 . The method of  claim 3  further comprising deleting by garbage collection aborted inflight replicated data. 
     
     
         10 . A non-transitory computer readable medium including program instructions for execution on a processor of a node, the program instructions configured to:
 receive one or more replicated snapshots at an instance of a snapshot storage service for storage and retrieval of snapshots, the snapshot storage service instance executing on a computing node proximate a primary site, the snapshots replicated in accordance with snapshot replication transfers of a replication transaction from a client;   mark the snapshot storage service instance to reject generation of new snapshots;   finalize the snapshots by completing index data structures configured to identify locations of the snapshots on an object store, wherein finalizing includes storing snapshot data and metadata as a service state of the snapshots committed to the object store;   terminate the snapshot storage service instance proximate the primary site;   instantiate another instance of the snapshot storage service at a secondary site; and   rebuild the service state of the another snapshot storage service instance from the object store and resume storage and retrieval operations of the snapshots serviced by the another snapshot storage instance.   
     
     
         11 . The non-transitory computer readable medium of  claim 10 , wherein the program instructions are further configured to, in response to the program instructions configured to mark the snapshot storage service instance, wait for inflight snapshot replication transfers to complete and finalize. 
     
     
         12 . The non-transitory computer readable medium of  claim 10 , wherein the program instructions are further configured to, in response to the program instructions configured to mark the snapshot storage service instance, abort inflight snapshot replication transfers after elapse of a configurable period of time. 
     
     
         13 . The non-transitory computer readable medium of  claim 12 , wherein the configurable period of time is set at a recovery point objective. 
     
     
         14 . The non-transitory computer readable medium of  claim 10 , wherein the program instructions configured to mark the snapshot storage service instance are further configured to assert a flag that indicates to the snapshot storage service instance to notify client to cease generation of new snapshots. 
     
     
         15 . The non-transitory computer readable medium of  claim 14 , wherein the program instructions are further configured to de-assert the flag to notify the client to resume replication of the snapshots to the another snapshot storage service instance at the secondary site. 
     
     
         16 . The non-transitory computer readable medium of  claim 14 , wherein the program instructions are further configured to de-assert the flag to notify the client to initiate further snapshot replication transactions to the another snapshot storage service instance at the secondary site. 
     
     
         17 . The non-transitory computer readable medium of  claim 10 , wherein the program instructions are further configured to determine committed snapshots during the rebuild of the another snapshot storage service. 
     
     
         18 . The non-transitory computer readable medium of  claim 10 , wherein the program instructions are further configured to delete by garbage collection aborted inflight replicated data. 
     
     
         19 . An apparatus comprising:
 a computer node having a processor configured to execute program instructions configured to:
 receive one or more replicated snapshots at an instance of a snapshot storage service for storage and retrieval of snapshots proximate a primary site, the snapshots replicated in accordance with snapshot replication transfers of a replication transaction from a client; 
 mark the snapshot storage service instance to reject generation of new snapshots; 
 finalize the snapshots with index data structures configured to identify locations of the snapshots on an object store, wherein finalizing includes storing snapshot data and metadata as a service state of the snapshots committed to the object store; 
 terminate the snapshot storage service instance proximate the primary site; 
 instantiate another instance of the snapshot storage service at a secondary site; and 
 rebuild the service state of the another snapshot storage service instance from the object store and resume storage and retrieval operations of the snapshots serviced by the another snapshot storage instance. 
   
     
     
         20 . The apparatus of  claim 19 , wherein the program instructions are further configured to, in response to the program instructions configured to mark the snapshot storage service instance, wait for inflight snapshot replication transfers to complete and finalize. 
     
     
         21 . The apparatus  claim 19 , wherein the program instructions are further configured to, in response to the program instructions configured to mark the snapshot storage service instance, abort inflight snapshot replication transfers after elapse of a configurable period of time. 
     
     
         22 . The apparatus of  claim 21 , wherein the configurable period of time is equal to a recovery point objective. 
     
     
         23 . The apparatus of  claim 19 , wherein the program instructions configured to mark the snapshot storage service instance are further configured to assert a flag that indicates to the snapshot storage service instance to notify client to cease generation of new snapshots. 
     
     
         24 . The apparatus of  claim 23 , wherein the program instructions are further configured to de-assert the flag to notify the client to resume replication of the snapshots to the another snapshot storage service instance at the secondary site. 
     
     
         25 . The apparatus of  claim 23 , wherein the program instructions are further configured to de-assert the flag to notify the client to initiate further snapshot replication transactions to the another snapshot storage service instance at the secondary site. 
     
     
         26 . The apparatus of  claim 19 , wherein the program instructions are further configured to determine committed snapshots during the rebuild of the another snapshot storage service. 
     
     
         27 . The apparatus of  claim 19 , wherein the program instructions are further configured to delete by garbage collection aborted inflight replicated data.